There's more to this than I could fit into a short piece. Classic research done in the 1940s, which factored into Brown v Board of Education, found that as young as 5, Black girls preferred White dolls to play with.

Recent study found similar preferences, with both White and Black children preferring lighter skinned cartoon characters. https://www.cnn.com/2010/US/05/13/doll.study/index.html